There are a few ways to get started, it depends on your budget, what you want to host, and what you don't. If you want something to host at home, and you have

There are a few ways to get started, it depends on your budget, what you want to host, and what you don't. If you want something to host at home, and you have sufficient bandwidth, a Raspberry Pi (4b) can get you started relatively cheap, with an external HDD/SSD. In terms of securing it, my recommendation would be that you don't expose your services themselves but setup a VPN you can access remotely and connect to that to use your self-hosted services. This may not always be convenient so you could expose specific services as required. Regarding the static IP (or lack of) you'll want dynamic DNS; I wrote a (simple) tool in Golang which I can compile to run on my (Ubiquiti, mips64) router, it uses Digital Ocean's API to provide Dynamic-DNS. If this doesn't appeal to you, a cheap $5 VPS on DigitalOcean or similar is a good place to get started too, you can use Let's Encrypt for free TLS certificates and there's plenty of help around to get started. Check out /r/selfhosted on Reddit, they're a helpful and friendly bunch.